In the technical field of chemical reactions, chemical reaction apparatuses are known in which various fluidized material mixtures are supplied to flow paths to cause chemical reactions, i.e., catalyst reactions with catalysts placed in the flow paths, thereby producing desired fluid materials.
These chemical reaction apparatuses have various scales and structures in accordance with their applications. For example, in a certain relatively small-sized chemical reaction apparatus, a micron-order or millimeter-order flow path is formed in a silicon substrate by using the micropatterning technique developed in the technology for fabricating semiconductors such as semiconductor integrated circuits, and a fluid is supplied to this flow path to cause a chemical reaction.
FIG. 25 is an opened-up plan view showing an example of such conventional chemical reaction apparatuses. FIG. 26 is a sectional view taken along a line B-B in FIG. 25.
This chemical reaction apparatus includes a silicon substrate 1. In one surface of the silicon substrate 1, a fine zigzagged flow path 2 is formed by using the micropatterning technique developed in the semiconductor fabrication technology. Various fluids for performing chemical reactions are supplied into the flow path 2. On the inner wall surfaces of the flow path 2, a catalyst layer 3 for performing a chemical reaction is formed as needed.
A glass plate 4 serving as a lid is stacked and bonded to the one surface of the silicon substrate 1. An inlet port 5 and outlet port 6 are formed in those two predetermined portions of the glass plate 4, which correspond to the two end portions of the flow path 2.
On the other surface of the silicon substrate 1, a thin-film heater 7 which is zigzagged in accordance with the flow path 2 is formed. If the chemical reaction (catalyst reaction) in this chemical reaction apparatus induces an endothermic reaction under predetermined heat conditions, the thin-film heater 7 supplies predetermined thermal energy to the catalyst layer 3 in the flow path 2 upon the chemical reaction.
An application of this chemical reaction apparatus having the above arrangement will be explained below.
For example, research and development for putting a power supply system using a fuel cell into practical use have been extensively done in recent years. A chemical reaction apparatus having the above arrangement can be used in this power supply system using a fuel cell. That is, by this chemical reaction apparatus, hydrogen can be produced from a power generation fuel gas and supplied to the fuel cell, and the power supply system using the fuel cell can be downsized.
While the thin-film heater 7 heats the interior of the flow path 2 to a predetermined temperature, the power generation fuel gas described above is supplied into the flow path 2 from the inlet port 5. This causes an endothermic reaction by the catalyst layer 3 in the flow path 2 to produce hydrogen and carbon dioxide as byproducts. Of these products, only hydrogen can be produced by removing carbon dioxide from hydrogen. Electric power can be generated by supplying this hydrogen to the fuel cell.
In the above conventional chemical reaction apparatus, the interior of the flow path 2 is heated by supplying electric power to the thin-film heater 7. Therefore, the heating temperature in the flow path 2 can be controlled relatively easily by controlling the electric power supplied to the thin-film heater 7. However, relatively large electric power is required for heating.
Also, since the thin-film heater 7 is formed on the other surface of the silicon substrate 1, the thermal energy is supplied to the catalyst layer 3 in the flow path 2 via the silicon substrate 1 and at the same time radiated to the surroundings. This increases the thermal energy loss and worsens the energy utilization.